US3835367A - Overload protection circuits - Google Patents

Overload protection circuits Download PDF

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Publication number
US3835367A
US3835367A US00332097A US33209773A US3835367A US 3835367 A US3835367 A US 3835367A US 00332097 A US00332097 A US 00332097A US 33209773 A US33209773 A US 33209773A US 3835367 A US3835367 A US 3835367A
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US
United States
Prior art keywords
resistor
voltage
thyristor
regulator
series
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Expired - Lifetime
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US00332097A
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English (en)
Inventor
D Wiley
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Lucas Electrical Co Ltd
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Lucas Electrical Co Ltd
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Publication date
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Publication of US3835367A publication Critical patent/US3835367A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
    • H02H9/041—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage using a short-circuiting device
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/06—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric generators; for synchronous capacitors
    • H02H7/067—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric generators; for synchronous capacitors on occurrence of a load dump
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S320/00—Electricity: battery or capacitor charging or discharging
    • Y10S320/13—Fault detection

Definitions

  • An overload protection circuit has a thyristor the anode and cathode of which are connected across a pair of supply lines requiring protection. Connected across the anode-cathode is a series circuit including a voltage dependent resistance and a resistor, the junction of which is connected to the gate of the thyristor. At the nominal voltage of the system, the voltage dependent resistance has a high value, but it has a substantially reduced value at voltages substantially above the nominal voltage of the system. The voltage dependent resistance protects the system against low current volts, and the thyristor is turned on for high current volts.
  • An overload protection circuit in accordance with the invention comprises a thyristor the anode and cathode of which are intended to be connected across a pair of supply lines requiring protection, and a series circuit connected across the anode-cathode of the thyristor and including a voltage dependent resistance and a resistor, the junction of which is connected to the gate of the thyristor, the voltage dependent resistance having a high value at the nominal voltage of the system, and a substantially reduced value at voltages substantially above the nominal voltage of the system, the arrangement being such that in use when a fault occurs such that current flows through the voltage dependent resistor, for low current faults the thyristor will not conduct and the system is protected by the voltage dependent resistor and resistor in series, but for high current faults the thyristor is turned on to protect the system.
  • said resistor is bridged by a Zener diode and a resistor in series, and the junction of the Zener diode and resistor is connected to the gate of the thyristor.
  • the voltage dependent resistor is preferably a Zener diode, and the resistor in series with the voltage dependent resistor is preferably chosen to have a very low inductance.
  • a printed circuit resistor is employed.
  • the invention resides in a battery charging system for a road vehicle, comprising in combination a generator having a field winding, a battery which in use is charged by the generator, a semiconductor voltage regulator for regulating the output of the generator by varying the current flow through the field winding, and a protection circuit for preventing destruction of the regulator by transients in the system, said protection circuit comprising in combination a thyristor having its anode-cathode path connected across the regulator, and a series circuit connected across the regulator and including a voltage-dependent resistance and a resistor, the voltage-dependent resistance having a high value at the nominal system voltage but a substantially reduced value when the voltage across the regulator rises above a predetermined value, the junction of the voltage dependent resistance and the resistor being connected to the gate of the thyristor, and the arrangement being such that if a low current transient occurs across the regulator, the regulator is protected by current flowing through the voltage dependent resistor and the resistor in series, but if a high current transient occurs, then
  • the voltage-dependent resistor is preferably a Zener diode.
  • the resistor is preferably a printed circuit resistor, or some other resistor having an extremely low inductance.
  • the resistor may be bridged by a Zener diode and a further resistor in series, with the junction of the Zener diode and further resistor connected to the gate of the thyristor.
  • FIG. 1 is a circuit diagram illustrating one example of the invention.
  • FIG. 2 illustrates a modification
  • a three phase alternator 11 which supplies power through a full wave rectifier consisting of two sets of diodes 12 and 13 to positive and negative supply lines 14, 15 between which the battery 16 of a road vehicle is connected.
  • the line 15 is earthed.
  • three auxiliary diodes 17 connected to the phase points of the alternator and providing power to a further positive supply line 18 which is connected to the line 14 through a warning lamp l9 and the vehicle ignition switch 21 in series.
  • the ignition controlled loads of the vehicle are indicated at 22 and are connected between the junction of the lamp l9 and ignition switch 21 and the line 15.
  • Loads 22 will of course include the contact breaker of the vehicle, which controls current flow in the primary winding of the vehicle ignition coil, the secondary winding of which is connected tothe plugs of the vehicle in turn through a distributor.
  • a resistor 24 and a pre-set resistor 25 Connected in series between the lines 18, 15 are a resistor 24 and a pre-set resistor 25.
  • the junction of the resistors 24 and 25 is connected through a Zener diode 26 to the base of an n-p-n transistor 27, the base along being connected through a resistor 28 to the line 15.
  • the emitter of the transistor 27 is connected to the line 15 and its collector is connected through a resistor 29 to the line 18, whilst its base and collector are bridged by a capacitor 31.
  • the collector of the transistor 27 is connected to the base of an n-p-n transistor 32 having its emitter connected to the base of an n-p-n transistor 33, the emitter of which is connected to the line 15 and the collector of which is connected to the line 18 through the field winding 34 of the alternator 11, the winding 34 being bridged by a diode 35.
  • the collectors of the transistors 32 and 33 are connected to the base of the transistor 27 through a resistor 36 and a capacitor 37 in series.
  • the lines 18, 15 are further bridged by two parallel paths, one of which contains the anode-cathode path of a thyristor 41, and the other of which contains a Zener diode 42 in series with a resistor 43, the junction of the Zener diode 42 and resistor 43 being connected to the gate of the thyristor 41.
  • the components 41, 42 and 43 do not conduct, and so for'the moment they can be ignored.
  • the ignition switch 21 When the ignition switch 21 is open and the alternator is not producing an output, then no current flows in any part of the circuit.
  • the battery 16 On closing the ignition switch 21, the battery 16 provides power to the loads 22, and current also flows through the switch 21 and the warning lamp 19, and thence by way of the resistor 29 and the base-emitter paths of the transistors 32 and 33 to energise the field winding 34, the lamp 19 being illuminated at this stage.
  • the potential of the line 14 When the engine has started and the alternator 11 is producing an output, then the potential of the line 14 is substantially equal to the potential of the line 18, and so the regulator is supplied with power by the lines 18, 15, and the warning lamp 19 is extinguished.
  • the transistor 27 is not conductive and the transistor 33 conducts to provide the required field current.
  • the Zener diode 26 breaks down to provide current to the transistor 27, which turns on to remove base current from the transistor 32 and thereby remove base current from the transistor 33.
  • the circuit oscillates between one state with the 33 is off, energy stored in the winding 34 causes current to flow through the diode 35.
  • the transistor 33 will cease to conduct, and the prevailing field current will then decay expotentially by way of the diode 35.
  • the voltage between the lines 18, 15 rises to a peak value. and then decays expotentially.
  • the peak value depends on the open circuit voltage characteristic of the alternator and its speed and output at the moment of disconnection.
  • the signal occuring between the lines 18 and 15 could have a peak value of 120 volts decaying expotentially over a period of 0.25 seconds, since a typical source impedance is about 1.4 ohms, it will be seen that if the transistor 33 breaks down, a large current can flow.
  • Zener diode 42 could be replaced by other forms of voltagedependent resistor, although the Zener diode is the preferred component. Any other form of voltage dependent resistor employed would have to have a substantial resistance at the nominal supply of the system,so that the normal conduction through the paths 42, 43 was small,'but a substantially reduced resistance at elevated voltages so that the protection circuit operates in the manner described. a
  • the resistor 43 should have an extremely low inductance, so as to minimise any possibility of unwanted triggering of the thyristor 41. Ideally this can be achieved by having a printed circuit resistor 43.
  • the Zener'diodes 42 and 51 used in FIG. 2 were 20 volt and 8.2 volt Zener diodes respectively.
  • a battery charging system for a'road vehicle comprising in combination a generator having a field winding, a battery which inuse is charged by the generator, a semi-conductor voltage regulator for regulating the output of the generator by varying the current flow through the field winding, and a protection circuit for preventing destruction of theregulator by transients in the system, said protection circuit comprising in combination a thyristor having its anode-cathode path connected across the regulator, and a series circuit connected across the regulator and including a voltagedependent resistance and a resistor, the voltagedependent resistance having a high value at the nominal system voltage but a substantially reduced value when the voltage across the regulator rises above a predetermined value, the junction of the voltage dependent resistance and the resistor being connected to the gate of the thyristor, and wherein the voltage developed across said resistor in series with said voltagedependent resistance, when the voltage across the regulator rises above said predetermined value, is insufficient to turn on said thyristor during the occurrence of a low current transient across
  • a system as claimed in claim 1 in which the voltvery low inductance. age-dependent resistor is a Zener diode, the voltage de- 5.
  • a system as claimed in claim 4 in which the resisveloped across said resistor in series with the Zener 5 tor in series with the voltage-dependent resistor is a diode at the instant when the Zener diode conducts printed circuit resistor. being insufficient to turn on said thyristor.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Emergency Protection Circuit Devices (AREA)
  • Control Of Charge By Means Of Generators (AREA)
  • Control Of Eletrric Generators (AREA)
US00332097A 1972-02-19 1973-02-13 Overload protection circuits Expired - Lifetime US3835367A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB778572A GB1424512A (en) 1972-02-19 1972-02-19 Battery charging system for road vehicles

Publications (1)

Publication Number Publication Date
US3835367A true US3835367A (en) 1974-09-10

Family

ID=9839675

Family Applications (1)

Application Number Title Priority Date Filing Date
US00332097A Expired - Lifetime US3835367A (en) 1972-02-19 1973-02-13 Overload protection circuits

Country Status (12)

Country Link
US (1) US3835367A (enrdf_load_stackoverflow)
JP (1) JPS547935B2 (enrdf_load_stackoverflow)
BR (1) BR7301174D0 (enrdf_load_stackoverflow)
DD (1) DD105353A5 (enrdf_load_stackoverflow)
DE (1) DE2308090A1 (enrdf_load_stackoverflow)
ES (2) ES411691A1 (enrdf_load_stackoverflow)
FR (1) FR2172332B1 (enrdf_load_stackoverflow)
GB (1) GB1424512A (enrdf_load_stackoverflow)
IN (1) IN138414B (enrdf_load_stackoverflow)
IT (1) IT977375B (enrdf_load_stackoverflow)
PL (1) PL84282B1 (enrdf_load_stackoverflow)
ZA (1) ZA73631B (enrdf_load_stackoverflow)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3938005A (en) * 1974-11-25 1976-02-10 General Motors Corporation Electrical generating system overvoltage protection circuit
US3944905A (en) * 1973-12-08 1976-03-16 The Lucas Electrical Company Limited Battery charging systems for road vehicles
US4136311A (en) * 1977-05-19 1979-01-23 Scheidler Ralph E Dual rate voltage regulator
US4349854A (en) * 1979-05-25 1982-09-14 Nippondenso Co., Ltd. Power generation control system for vehicle generator
US4401937A (en) * 1977-11-02 1983-08-30 Mitsubishi Denki Kabushiki Kaisha Control device for battery charging AC generator
US5264988A (en) * 1986-07-19 1993-11-23 Ken Hayashibara Circuit to limit surges into a dc-operated lamp
US5805394A (en) * 1997-06-17 1998-09-08 Sundstrand Corporation Overvoltage protection circuit for a generating system utilizing a fault current sensing Circuit in combination with a shunting circuit
US20050146309A1 (en) * 2004-01-06 2005-07-07 Visteon Global Technologies, Inc. Alternator rectifier
CN101483333B (zh) * 2007-12-28 2011-07-27 车王电子(宁波)有限公司 发电机的短路保护装置

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5825731Y2 (ja) * 1976-01-27 1983-06-02 ヤマハ発動機株式会社 車両用サ−ジ電圧吸収装置
DE2708981A1 (de) * 1977-03-02 1978-09-07 Bosch Gmbh Robert Einrichtung zum schutz einer elektrischen anlage
JPS543315U (enrdf_load_stackoverflow) * 1977-06-10 1979-01-10
JPS548847A (en) * 1977-06-22 1979-01-23 Hitachi Ltd Surge protection circuit
JPS5448324U (enrdf_load_stackoverflow) * 1977-08-12 1979-04-04
DE3738503C1 (en) * 1987-11-13 1989-03-02 Daimler Benz Ag Vehicle on-board electrical power supply system
FR2664759B1 (fr) * 1990-07-13 1996-09-27 Sgs Thomson Microelectronics Dispositif de protection contre des surtensions.

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3436639A (en) * 1967-03-06 1969-04-01 Mcculloch Corp Voltage cut-off circuits
US3488560A (en) * 1967-05-01 1970-01-06 Gen Motors Corp Transient potential protection circuit
US3740637A (en) * 1971-08-31 1973-06-19 Nippon Denso Co Automobile battery charger with protection means

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3454860A (en) * 1966-02-25 1969-07-08 Mcculloch Corp Voltage cut-off circuits
JPS4420750Y1 (enrdf_load_stackoverflow) * 1966-05-06 1969-09-04

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3436639A (en) * 1967-03-06 1969-04-01 Mcculloch Corp Voltage cut-off circuits
US3488560A (en) * 1967-05-01 1970-01-06 Gen Motors Corp Transient potential protection circuit
US3740637A (en) * 1971-08-31 1973-06-19 Nippon Denso Co Automobile battery charger with protection means

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3944905A (en) * 1973-12-08 1976-03-16 The Lucas Electrical Company Limited Battery charging systems for road vehicles
US3938005A (en) * 1974-11-25 1976-02-10 General Motors Corporation Electrical generating system overvoltage protection circuit
US4136311A (en) * 1977-05-19 1979-01-23 Scheidler Ralph E Dual rate voltage regulator
US4401937A (en) * 1977-11-02 1983-08-30 Mitsubishi Denki Kabushiki Kaisha Control device for battery charging AC generator
US4349854A (en) * 1979-05-25 1982-09-14 Nippondenso Co., Ltd. Power generation control system for vehicle generator
US5264988A (en) * 1986-07-19 1993-11-23 Ken Hayashibara Circuit to limit surges into a dc-operated lamp
US5805394A (en) * 1997-06-17 1998-09-08 Sundstrand Corporation Overvoltage protection circuit for a generating system utilizing a fault current sensing Circuit in combination with a shunting circuit
US20050146309A1 (en) * 2004-01-06 2005-07-07 Visteon Global Technologies, Inc. Alternator rectifier
US7084610B2 (en) 2004-01-06 2006-08-01 Visteon Global Technologies, Inc. Alternator rectifier
CN101483333B (zh) * 2007-12-28 2011-07-27 车王电子(宁波)有限公司 发电机的短路保护装置

Also Published As

Publication number Publication date
DE2308090A1 (de) 1973-08-23
JPS4894844A (enrdf_load_stackoverflow) 1973-12-06
FR2172332A1 (enrdf_load_stackoverflow) 1973-09-28
FR2172332B1 (enrdf_load_stackoverflow) 1978-03-10
ZA73631B (en) 1973-10-31
JPS547935B2 (enrdf_load_stackoverflow) 1979-04-11
PL84282B1 (enrdf_load_stackoverflow) 1976-03-31
ES414463A1 (es) 1976-02-01
GB1424512A (en) 1976-02-11
ES411691A1 (es) 1976-01-01
AU5184673A (en) 1974-08-08
DD105353A5 (enrdf_load_stackoverflow) 1974-04-12
BR7301174D0 (pt) 1973-10-09
IT977375B (it) 1974-09-10
IN138414B (enrdf_load_stackoverflow) 1976-01-31

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